Current regulator



July l5 1924. 1,501,395 K. CRITTENDEN CURRENT REGULATOR Filed Jan. 1e. 1922 Pmnfea Jaly'15,f1924.

UNITED STATES l f www PATENT OFFICE.

:man: cmmnm, or magnum nu, moment.

cUnnnN'r REGULATOR.;

. appummmea January 1e, im. sei-m no. 596,515. t'

To all whom 'it may concern.' v

Be it known that I, KENNETH CnrrrnN-y DEN, a citizen of the United States of America, residin at Highland \Park, in ,the county of ayne and Statepof-Michi an, have invented certain'new and useful provements inurrent Regulators,'of which' the following is a specification, reference being had therein to the accompanying draw- This invention relatesto means for autov matically regulating the current output of` a generator, and more particularly 'to a cum. rent regulatorand cut-out for battery charg-u in'g circuits especially designed for installation in lighting, ignition, and-other systems Ausually employing an internal combustion engine ast generator. A

An object of the invention is`to effect an e prime .mover for. driving the automatic and accurate regulation of they generator current output and battery charg- T ing rate.' A yfurthe` object is 'toprovide an automatic batterycut-out in connection with such generator regulatingmeans and to pro nvide a device of simple construction which is compact inxits arrangement and eiiicient in operation, being especially adapted for use in connection with-a' shunt wound gnerator for battery charging circuits of motor vehicles. D T With the above and other ends in view, the invention' consists in providing a variable resistance for varying the field current of the generator and in establishing a magnetic balance for controlling the variable resistance -in accordance with variations in` the speed'of the generator armature.

The invention also consists in providing certain other newfand useful features and in the construction and arrangement of parts,

all as hereinafter more fully described and particularly set forth in the appended claims, reference being had to the accompanying drawing, in which Figure 1 is a longitudinal vertical section through a device illustrative of the invention;

Fig. 2 is `a top planA view'of the same;

Fig. 3 is a bottom planfview, and Fig. 4 is a Wiring diagram. As shown in Fig. 4, 1 indicates the armature-shaft of a shunt wound generator, 2`the` positive fbrush, and v3 the negative brush. of

the enerator. y4 indicates the field winding' of t e generator which is connected at one lbrush 2oft end to the ound wire 5 of the negative brush and t e o posite end of the winding is connected b t e wire 6 to the terminal of the contro ing device which is indicated as a wholeby the numeralA 8. -Thepsitive wire'9 to a terminal or' lead' 10 of the controlling device and a storage battery 11 is connected by the wire 12 to the terminal 13 l of the controlling device.

Describin ,in general the construction and operation o the device embodying the invention, and refe particularly to Fig. 4 of the drawing hen the prime mover (not shown) for drivin 'the generator ar-' mature is started, the slig t current from the residue of ma etism in the pole pieces of the generator 1s collected by the generator commutator and flows to the positive brush 2, thence through the lead 9 to the frame 14 ofi the controlling device; and from said frame to the movable core or lunger 15 of a magnetic device or solenoid indicated as a whole by the numeral 16, andn whichsolenoid e generator is connected by a' is mounted upon the frame 14. The current point where itexceeds that of the battery,

and the current flowing thugh the frame 14 and stationary core 19 of the solenoid 16,

j,passes through la shunt coil 20 ,which is wound uponvthe core with one end connected to the core and its opposite end grounded, as

and through thec lead 18,

shown at 21. This shunt coil is of vhigh resistance and the small percentageof current passing through'it creates a magnetic pull upon the armature 22 which extends across the upper/,end of the core 19 and is pivoted at. one end, as at 2K3, to a side leg of the frame 14, its opposite end carrying a contact'24 to engage a like contact 25 carried'by the opposite side leg of the` frame.v This electrosmagnetformed by the .winding of the high resistance shuntcoil 2O upon ,the core 19, thus serves to o ,erate the armaturet22 against the action o a spring 26 and close` the circuit through alow resistance series coil 27 which is also wound upon the core 19 outside of the coil 20, one end of this series coil 27 being electrically connected to the contact "25 and its opposite end, to the terminal 13, vwhich terminal is connected to the battery 11 by the lead 12, so that when the speed of the generator armature reaches a predetermined charging rate, the electromagnet will operate to close the battery cir-- cuit and after the circuit is closed by the armature 22, said armature will be held closed not only by the pull thereon caused by current passing through the shunt coil but also by the current passing through the -low resistance series coil 27 tothe battery. e v

Further increase in speed of the generator armature causes a further increase in cur-y rent whichrapidly buildsjup to a predetermined battery charging rate, when the `magnetic .pull on the 'plunger or movable core 15 caused bythe passage of current through thelcoils 20 and 27 will tend to separate the contacts 17 which are connected in the vdirect circuitof the generator field,

and as these jcontacts are preferably of a very high resistance material, such .as tungsten, the variations in the force with which the contacts are pressed together,

. generator.

will. provide' a variable resistance in the field curren't of the generator. The contacts 17 are normally held in enga ement with each other by a spring 28 (see. ig. 1) which is located within a bore in the inner end of the plunger 15 and exerts a force to hold the plunger moved endwise from the core A resistance coil 29 is also yconnected in the generator field circuit, in parallel with the contacts 17 said resistance coil being, for the purpose of convenience and compactness of arrangement, wound about the coils 20 and 27, but in a' reverse direction, one end of said coil 29 being connected to the frame -14 and its opposite end electrically connected to the termmal ,7, to which terminal, the

lead 18 from the stationary contact 17 is also connected. A portion of the field current therefore Hows through the frame 14 coil 20 and thence through the resistance coil 29 in a reverse direction to the flow of current through the low resistance coil 27 and shunt and therefore, the magnetic pull of the coil 29 normally opposes the action of the shunt coil 20 and series coil 27 to momentarily resist the separation of the contacts 17..

A magnetic balance is therefore set up between the windings of the solenoid andthe spring 28 which will lgive constant voltage and current from positive to` Vnegative brushes of the generator, by varying the field current with the speed of the armature through the variable resistance set up within the field circuit by varying the contact pressure of the contacts17: A constant current output of the generator is therefore maintained until the speed of the generator armature reaches a predeterminedv point,

which will be the maximum battery charge ing rate, when the magnetic pull of the series coil 27 .and the shunt coil 20 will be suiicient to overcome -the bucking action of thecoil 29 and the'inechanical resistance of 'the spring 28,' and the 4 'zontact points 17 lwill 'be separated. This will reduce the charging rate of the generatorby cutting down the field current to theflow through the resistance coil 2 9. When the speed of the generator armature decreases`so that the voltage generated falls below battery voltage, current will iow back from the battery through the series coil 27, changing the polarity of this coil so that it will buck .or opposethe shunt coil 20 which is very weak-because of the low voltage which is being generated, and therefore, the pull of the electromagnet will be reduced to such an extent that it Will be overcome by the action of the spring 26 and the armature .22 will move away. from the end' of the magnet, separating the contacts 24and 25 and breaking the circuit of the coil 27 which is the battery circuit, thereby cutting out the battery.

In order to providea simple device having acom act arrangement which is particularly app -icable for use in connection lwith generators commonly employed for generating'battery' charging current in motor vehicle constructions, a specific form and arrangement ofparts which have been pre-- viously described in a general way, is'shown in Figs. 1 to 3 inclusive, of the drawing.

-This specific embodiment of the invention comprises a base or4 supporting frame 30 Which is provided with suitable laterally extending supporting legs 31 by means of which the device may. be conveniently attached to a casing of a generator. Mounted upon this base and suitably insulated therefrom, v is ,the U-shapd :frame 14 Tand art rangedy centrally within this frame is the fixed core 19 of the electro-magnet, the lower iis end of this core extendingthrou'gh an opening in the horizontal member o the frame 14 and electrically connected with the frame.

The core is bored inwardly from its lower end to receive the movable core or plunger 15, which plunger projects beyond the lower end of the fixed core and carries one of the contacts 17, the fixed opposing contact being carried by the-base 30, but insulatedlfrom thebase. l vThe inner end of the plunger is bored axially to receive the spring 28 which is interposed between the inner en'd of 5 vthis ,bore and the inner end of the bore of I the core 19. Wounddirectly'upon the fixed core '19, is the shuntkcoil 20 with one endv support for the contact member 25. The op' posite end of the coil 27 is ledout through an opening in the base 30 and across the base to a member carried bythe base and insulated therefrom and' forming theter-l minal 13 to which the lead 12 runningto the battery is connected. The hi h resist ance coil 29 of fine wire is woun outside the coil 27 with one end of the wire 29 electrically connected to a side leg of the lframe, as at 34 and through this frame, the terminal 10 and wire 9 with the positive brush of the generator. he oppositefend of this wire formin the coil 29 is led to a post 35 carried 30 by the'. ase `30 and insulated therefrom and to which post the fixed contact 17 is electrically connected by the lead or member 18 which' has a laterally extending arm forming the terminal 7 towhich the Wire 6 leading to the generator field, is attach l By arranging the contacts 17 at .one end of the movablecore or plunger of the electro-magnet, arcing at these contact points is practically eliminated by the action of the magnetic lines of force which pass around the end of the plunger through the gap be-v tween the contacts, and thus an action similar to a magnetic blow ot'coil is secured,

burning of the contact oints.

It is not essential to t e "operation of this device that the resistance coil 29 be wound for opposite polarity to that of the shunt' ment of the parts may be made,within the scope of the appended claims, withoutde parting from the spirit of the invention, and I do not therefore limit myself to the particular construction shown.

lwhich effectually prevents arcing and the' Havin' thus fully described my invention,

what I' c aim is 1., A' device of the character described comprising a ylJ-shaped frame having an opening in thehorizontal member thereof, 'a fixed core mounted upon said frame with one end secured within'said opening and extending therethrough,v a Vmovable core vwithin the fixed core and extending through the opening in the frame, a low resistance series coil -wound upon the fixedv core for connection in a. battery circuit, an armature on the frame and extending across an end of the-fixed core and connected in a battery circuit to `open and close the'same, a shunt coil wound upon the fixed corevwith vone end electrically connectedto the core and vits oppositeend grounded, variable resistance means for connection within a -field circuit, and comprising a` fixed contact member carriedby the frame,and a movable contact member carried by the movable core, and a high resistance 'coil connected in the field vcircuit inparallel with said variable resistl ance means.

, 2. A device of the character-described comprising a 'U-shaped frame, a hollow fixed core mounted in the frame, a movable core in the fixed core, a s ring to resist the movement of the movable core in one direction of it's movement, a low resistance series coil wound uponthe fixed core, a shuntcoil upon the fixed core, an armature carried by the frame and adapted to be operated by thev magnetic effect of current passing through said coils, said armature eing connected within the circuit of the lowv resistance coil 'to open and close said circuit, a. springV to resist the movement of the armature againstthe magnetic pull thereon, variable resistance means -for connection within a field circuit of a generator and comprising a fixed contact an`d a co-operating movable contact carried by the movable core, and a hi h resistance coil for connection inthe fie d circuit, in. parallel with said Kvariable resistance means.

.3. A device of the character described comprisin a base, a U-shaped frame mounted Aupon t e base Aand insulated therefrom, said frame having an opening in its horizontal portion, a fixed core carried by the frame with one end secured within and ex'- tending through the opening in the frame,

a movable core in the fixed core, with one end of the movable core projecting from the fixed core, a spring to resist the movement -of the movable core in one direction, a shunt coil wound upon the fixed core with one end electrically connected with the core and the opposite end tothe ground, a low resistance series coil wound upon the fixed core with one end adapted for connection to a battery circuit, a, contact member on .the frame to which the opposite end of the series coil is y connected, en armature extending across the being wound upon the series coil andshunt frame and across the upfer end of the fixed coil, with one end of said high resistance coil core to move toward an from the core and 'connected to the frame land its o posite end having a. content to engage the contact mcmadapted for connection in the eld circuit. 15

-ber on the' frame, variable resistance means In testimony whereof I aflx my signature for cnnectioi within afieldciruit of a in presence of two witnesses.

enerator an com risin a. Xe contact" gud a co-operating Ililovab e contact carried KENNETH CRITTENDEN by the movable core, and a, high resistance Witnesses: Y 1.0 coil connected in parallel With'said variable ANNA M. Donk,

resistance means, said high resistance coil LEWIS E.\.FLANDERs. 

